The present invention relates to the field of cardiac assist devices, such as blood pumps and the like. More specifically, the present invention relates to a cannula tip for use at the inflow of a blood pump that is designed to avoid the creation of a suction condition.
Bypass type cardiac assist devices are used frequently in advanced stages of heart failure to assist the failing human heart. It is typical for such devices to be used as left ventricular assist devices (LVAS) or right ventricular assist devices (RVAS).
Approximately 30% of the deaths of LVAS patients are the result of excessive venous pressure, increase in the hepatic portal vein pressure, and multi-organ failure. Over 60,000 patients a year who experience heart failure will require cardiac assist devices.
One problem associated with an implanted cardiac assist device is decreased pump flow volume which may result when the inflow cannula tip becomes attached to the ventricle wall resulting in a “suction condition”. In addition to decreasing the pump flow volume, such a suction condition will also limit the output of the natural heart, leading to sudden decrease in blood pressure, blood circulatory failure, and possible death.
The suction condition is more prevalent with a right ventricular assist pump. The inflow conduit of a right ventricular assist pump is inserted directly through the right ventricular wall near the pulmonary arterial valve. Anatomically there is not enough space available at this location between the right ventricular wall and the septum. Thus, a suction condition will occur easily unless a proper inflow tip is provided.
This suction condition may be caused by improper positioning of the cannula tip, excessive pump flow volume, outside pressure of the heart, etc. It is imperative to prevent the occurrence of such a suction condition.
A further problem associated with implantable cardiac assist devices is platelet adhesion on the inflow cannula tip, leading to the clots which reduce and ultimately prohibit blood flow.
It would be advantageous to provide a cannula tip for use at the pump inflow which is shaped to avoid the occurrence of the suction condition. It would also be advantageous to provide an inflow cannula tip that is resistant to platelet adhesion and the formation of blood clots.
The inflow cannula tip of the present invention provides the foregoing and other advantages.